HOME improvement programmes such as Grand Designs and House Doctor have us glued to the television during the week.

HOME improvement programmes such as Grand Designs and House Doctor have us glued to the television during the week.

At weekends, it's time for action as we spread the dust sheets, roll up our sleeves and get stuck into do-it-yourself projects.

New research from Alliance & Leicester shows that spending on DIY is set to soar this autumn, up from an average #1,208 in the summer to a planned #1,270.

And the reason is simple. Five Bank of England base rate rises in nine months have put a different slant on matters.

As house prices remain high and mortgage payments head upwards, many are now having second thoughts about moving up the property ladder.

Paul Cooper, head of mortgages at A&L, says: "Although we have seen a fall in the proportion of people planning to move house over the next three months, the increase in predicted DIY spend suggests that rising interest rates may be influencing buyers to hold back and focus on their properties until rates stabilise."

Decorating remains the most popular DIY activity with 29% of people planning to add a new carpet, curtains or furniture, followed by painting (19%) and garden improvements (10%). But bigger home improvements are still popular, with seven per cent planning to fund a new kitchen and six per cent a new bathroom.

While improving your home may sound like a good idea, particularly if you are planning to sell, those weekends spent in out-of-town DIY sheds are no guarantee of ample returns once it's time to move on, however.

DIY enthusiasts tend to believe that whatever they spend will add the same amount to the value of their home. Sadly, it does not always work out that way. While some home improvements can add considerable value, others do not even begin to pay their way.

For example, if you are planning to dig up your garden to put in a swimming pool, think again. Unless your house is worth #400,000 or more and has spacious grounds, a pool will almost certainly make your home more difficult to sell.

Pools are expensive to install, typically costing #15,000, and are not cheap to maintain at about #500 a year. They also tend to put off certain buyers, for example families worried about the safety of young children. The 48-hour makeover may work on Ground Force, but in the real world it has little financial value.

John Coleman, of estate agents Knight Frank, says before you start any major project you should carefully consider the value it will add.

"Home improvements must be appropriate to the market. A deck will be desirable in parts of Edinburgh, but may look out of place in rural Wiltshire. A Smallbone kitchen will definitely be worth the outlay for a country house in Oxfordshire, but you're unlikely to recoup the cost in some areas.

"Most importantly, a bad DIY project will always detract from the resale value. Anything that looks unprofessional, such as a badly fitted kitchen or uneven plastering, will get buyers asking questions and dropping offers."

According to Daily Post columnists and interior experts Justin Ryan and Colin McAllister, understanding regional tastes is the key to long-term profits. The pair experienced this phenomenon first hand when they scoured the country developing homes for their BBC series The Million Pound Property Experiment.

They have recently been drawing in huge audiences for their Channel Five programmes The Twenty Quickest Ways to Make Money on Your Property and How Not To Decorate, which finished its run yesterday.

Ryan says: "Because English houses are sold on the basis of values per square foot, you can really add value in the south through extensions and conversions."

If you add an extra bedroom or family room in the North, you might add #5,000 to your home's value. In London, shaving something off the garden to make way for a garage or parking spot or transforming an attic can add #50,000.

McCallister says: "We have friends who were saying how difficult it is to park in London. We suggested what they should do is buy somewhere with a tiny front garden and then apply to the local council to drop the pavement and create a parking space.

"You can add a considerable amount of value to your property in London by doing something like that."

It is a different story where space is less of an issue. Ryan adds: "In one northern city a friend increased the value of her home by #70,000 just by spending #20,000 on a new kitchen."

The boys recommend speaking to an estate agent to see what type of home improvements will add the most value in your area. This is something they learnt the hard way while working on The Million Pound Property Experiment.

"We did a house up in Harrogate and put in an open plan kitchen," Ryan explains. "It was a disaster for us as the only people who came to look at the house were families and all were worried about smells permeating through the home and keeping the kids out of the kitchen.

"We didn't plan and address our market - and that is important in any property development."

So for those hoping to make a decent profit on their largest asset, the real question is, which home improvements pay - and which don't?

Conservatories>Conservatories are one of the most popular home improvements and can be a good investment.

But it is important to make sure the new extension is in keeping with the rest of the house and does not use too much of the garden.

Conservatories can cost between #10,000 and #40,000 to build but, in the right circumstances, you can expect to recoup most of that.

As always, location is key. A spacious conservatory or loft conversion in a popular area will almost certainly increase value. In an unpopular area, however, it can be a waste of money.

Loft conversion>These should not be undertaken lightly. These usually require planning permission, can cost up to #20,000 and may take up to three months' work..

On the upside, an extra bedroom or bathroom will appeal to more buyers and can drive up the price of a home by as much as 10%.

Central heating>This is one of the few additions guaranteed to recoup all of its initial cost as it is virtually essential for any desirable house these days.

Garages>Creating a garage is another safe bet as off-street parking is always in demand in cities and towns.

You may require planning permission from the council, but this is an investment that will definitely prove worthwhile.

An investment of #6,000 to #10,000 could net as much as #30,000 to #50,000 later, depending on where you live.

Kitchens>Most buyers want a modern, fitted kitchen. That said, you are unlikely to recoup much of the cost, so avoid the dream kitchen at #25,000 and go for something more affordable.

Bathroom>A new bathroom is also an asset. A fully-fitted classic white bathroom is always a good investment. If you spend #2,500 to #7,500 you will get at least that amount back.

Other improvements>Regardless of the expense there are some improvement costs that you have to grin and bear. Maintaining gutters, fences and hedges is essential. You won't recoup the cost of this kind of work, but you neglect it at your peril.

A lick of paint in the right place can be worth thousands.

Damp proofing and repairing roughcast needn't cost the earth if problems are tackled at the outset. Similarly, you should pay close attention to garages, sheds and flat roofs.

Double glazing>Once seen as the height of luxury, it has fallen out of favour. This is because modern windows are thought to detract from older homes that retain other original fittings. Instead, opt for secondary glazing, which can be installed behind the original windows.

Other turn-offs include dividing a room into two or turning a bathroom into a bedroom. Both instantly damage a home's value.

Gaudy interiors may also makes homes harder to sell. Stick to neutral colours which will appeal to most and make rooms look brighter and bigger.